$3d^{10}4s^0$ electronic configuration is exhibited by

Which element from the following exhibits the lowest number of different oxidation states?

Which of the following compounds is expected to be coloured?

In the series $Sc (Z=21)$ to $Zn (Z=30)$,the enthalpy of atomisation of zinc is the lowest,i.e.,$126 \ kJ \ mol^{-1}$. Why?

Fill in the blanks:
$(a)$ The ground state electronic configurations of $Cr$ and $Cu$ are .......... and ..........,respectively.
$(b)$ Transition elements exhibit certain characteristic properties due to partially filled $d$-orbitals.
$(c)$ The general electronic configuration of transition elements is .......... .

Which of the following is not a transition metal?